The eldest son of Valdemar I, Cnut VI saw Denmark's influence spread definitively over Pomerania as well as holding off Imperial ambitions for the time being.

Firstly however Denmark was ravaged by peasant revolts. The Hvide family, most notably Bishop Absalon, virtually ran the government and excessive taxes had driven the peasants to raise an army to oppose the Bishop's men. The rising was comprehensively crushed by various lords. However Cnut appeared unhappy with the way his lords had proceeded without his presence, possibly thinking they let the peasants off lightly, and the ensuing squabbles stopped short of a civil war thanks only to desperate diplomacy. Cnut, much like his predecessors soon left domestic policy to those who knew better.

In 1184 Emperor Frederick I demanded Cnut acknowledge him as overlord of Denmark, a step up from Valdemar I's deference to him. Naturally Cnut refused and, with other matters to personally attend to in the south, the Emperor authorised the Duke of Pomerania to invade. Eager to free themselves of Danish interference the Pomeranians raised an army and a fleet but the Danes were sufficiently warned by their Rugian vassals and the invasion was defeated. Frederick would have to grudgingly accede to continued Danish independence. More than that Cnut IV led three invasions of Pomerania and the Pomeranian dukes were forced to switch their allegiance to Denmark rather than Germany. Cnut also led a crusade into Estonia in 1197, creating the Duchy of Osel (see Saaremaa) and beginning six centuries of direct rule.

Towards the end of his rule Cnut faced a rebellion by those supporting his younger brother Magnus, principally the Archbishop of Bremen, Niels Knudsen (himself an illegitimate Estridsson descended from Cnut III of Viken). Magnus was used as a pawn by Bishop Niels to further his own ambitions, namely to seize the throne of Denmark for himself. Magnus however realised what was happening and pledged allegience to Cnut. The bishop was not to be deterred however and received backing from the Imperial court to build a fleet and claim the Danish throne, assisted on land by the Count of Holstein. The alliance was defeated however and both archbishop and count were imprisoned.

Dying suddenly in 1202, Denmark was inherited by Magnus who would lead Denmark into a glorious age. Cnut IV only had illegitimate children and his wife, Gertrud of Saxony had taken a vow of chastity.